Thread rolling attachment



April 4, 1961 E. W. BRINKMAN THREAD ROLLING ATTACHMENT Original Filed March 16, 1954 F' .4 J2 if @H B" MW THREAD ROLLING ATTACHMENT Continuation of application Ser. No. 416,610, Mar. 16, -1954. This application June 20, 1958, Ser. No.

i "4 claims. (ci. lso-6) Thislinvention relates to a pattern rolling attachment arranged to be operated from the cross slide Yof an automatic screw machine or the, like for rolling knurls, screw threads, splines, and for forming thefteeth on small pinions yand other work pieces. `This application Yis a continuation of my application Serial No. 416,610, led March 16, 1954; now abandoned. Y

Since the rolling of patterns such as `knurls, screw threads and the like on metal stock, is a cold-forging process in which the patterns or knurls are formedby displacement `of the Vmetal of the stock, considerable side pressure is applied to the stock in effecting this operation. 'Ihis large side pressure present-in conventional knurling, thread rolling `and the like attachments, tends to bend the work stock since the rollers of such attachments areV advanced `into the work in a xed preset condition. To overcome this tendency toward bending, conventional attachments haverequired the use of a work support to oppose the side thrust of the work. However, such a support takes up a spindle or end working positionof the screw Vmachine which otherwise could bev utilized for drilling, tapping, or any other extra machining operation that may be necessary.4 v

The main feature of the present invention relates to the provision of a pattern rolling attachment in which the pattern forming rolls while in open or separated condition are advanced to the center line of the work to straddle it after which ,the rolls are closed against the opposite sides of work at the center line, thereby eliminating any unbalanced side pressure which might bend the work.

Another feature of the invention relates to keeping the pattern rolls in synchronism while they are being rotated by the work, such as by means of an interconnecting train Y of gears or the like, whereby more accurate patterns such as knurls or threads are produced on the work and longer threads, in relation to the thread `diameter can be made,

States Patenti- Patented-Apr. 4, 1961 ice performed by the machine, are effected in proper timedsequence. The cam 5 operating through a suitable cam lfollower 7, advances a connecting rod 8 toward the left in Fig.` l. This rod is pivotally connected at 9 to one arm of a lever 10 which is fixed to a shaft 11. This l shaft` is adapted to rock in suitable bearings 12 carried on the frame F. The other; arm 13 of the lever 10 is pivotally connected to the stem 14 of a T-shaped link l5. The ends of the cross arms 16, 16 of this link are pivotally connected respectively to the uprights 17, 17 of a yoke type link 18 provided at its intermediate point with These arms rock about-the spaced, parallel axes or fulthan can be effected on conventional thread rolling attachments. 1

Other features and advantages will appear from the detailed description and claims when taken with the drawings in which: r Y

Fig. l is a side elevation of the pattern rolling attachment ofthe present invention, shown in an intermediate stage in'its cycle of operation, together with a fragment of the machine with which it cooperates;

Fig. 2 is a front elevation of the attachment in the `same stage and a portion of the machine;

Figs.`3, 4, 4A and 5 are diagrammatic showings of the relation of the knurling rolls and the work in several of crums A, A, which are fixed on a vertical slide 31 and which extend at right angles to the plane of movement of the slide. The lower end of each rocking arm 2S rotata-` bly carries a pattern forming roll 32 therein illustrated as a knurling roll. It will be understood that these rolls are.

adapted to be driven by contact with thefrotating work W which is driven by the rotating collet C and related' Well-known means (not shown). The axes of the pattern rolls 32, which are parallel-to ,the axes of fulcrums A,

have xed thereto gears 33 and 37 which mesh with aV train of gears 34, 35 and 36 mounted and concealed in housing H, whereby the pattern rolls 32 aredriven in synchronism.

The previously mentioned slide 31 which is mounted for limited vertical reciprocatory movement in a direction at right angles tothe axis of the work, is mounted in a suitable guide in the frame, and is connected to the yoke link 18 by a rod 38. This rod extends into a circular bore (Fig. l) inthe slide at the bottom of which bore the lower end of the rod is screwed into the slide. The upper end of rod 38 passes through a clearance hole in yoke 18 where adjustable check nuts 39 limit the downward movement of the rod with respect to the yoke. A sleeve 40 encircling the rod, rides on the wall of the bore to have the stages of operation thereof. In Fig. 3 the rolls, still position separated from the work after it has been knurled; and

its upper end engage the check nuts 39. A spring 41, encircling the rod 38, has its lower end engaging the portion ofthe slide at the bottom of thebore and has its Vupper end engaging the bottom end of the sleeve. .This

arrangement serves, in the rest'condition of the attachment, to maintain a given spaced relation between yokel and slide 31. The downward movement of the slide is determined by a `fixed stop 43 on the slide base, which stop is contacted by an adjustable bolt 44 carried on the extensionV 45 of the slide 31. From the foregoing it will l be understood that the `slide serves to carry the toggle and the rockingarms 28 with their knurling rolls 32 to a position wherein these rolls are located,V on the centerline of the work W at opposite sides thereof (Fig. 3). j' y In the operation of the pattern rolling attachment, as the timing shaft 6 of the screw machine continues to rotate the cam 5, the high area thereon moves the rod 8 toward the left. The rod 8 elevates the left arm of the lever f 10 which is fixed to the shaft 11. The shaft 11 rocks in The Vlowerends of toggle arms 25 and 26 are pivoted respectively to the rocking arms 28.,

bearings 12 to advance the lever arm 13, downward. This arm acting through the links 15 and 18, simultaneously lowers the toggle joint andthe slide 31, until the slide strikes the xed stop 43 at which time the knurling rolls 32 stillin open conditionhave been lowered to the center line of the work W (Fig. 3). Further downward movement of the lever arm 13 acting through the links 15 and 1S forces the toggle joint downward to strongly force the knurling rolls 32 inward into the opposite sides of the work (Figs. 4 and 4A), so that the rolls engage the work at opposite sides thereof with the axes of the rolls and work lying in a common plane. The work, which is held in the rotating collet, ro-tates the knurling rolls as they roll knurls into the work. The knurling rolls, being interconnected through the train of gears 33, 34, 35, 36 and 37, are driven in synchronism.

The cam 5 and related parts hold the rolls 32 against the work until finished knurls are rolled thereon. The cam surface thereupon falls away so that the rod 8 proceeds to move toward the right. This causes lever arm 13 to rise. As this arm rises carrying the links 15 and 18 upward, link 18 elevates the toggle joint whereby the lower ends of the toggle arms 25 and 26 swing the knurling rolls outward away from the work (Fig. 5). As the lever arm 13 continues its way upward, the yoke link 18 engages the check nuts 39 and elevates the rod 38 and with it the slide 31. This upward movement of the slide, acting through swinging arms 28, elevates the pattern rolls 32 to clear the work. The attachment is now in its normal or rest position in readiness to repeat its described cycle of operation.

While the pattern rolls have been illustrated herein as knurling rolls 32, it will be appreciated that various other pattern forming rolls such as thread forming rolls 32a (Fig. 6) can be employed in the present attachment.

It will be understood that there can be numerous modications and variations in the present pattern rolling attachment, within the scope of the appended claims, without departing from the spirit of the present invention.

Having thus described my invention what I claim is:

l. An attachment for an automatic screw machine for rolling a pattern on a rotating workpiece, which screw machine has a rotary work support for the workpiece that is rotatably driven during operation of the machine, said attachment compiising a rectilinearly-movable slide, a support on which said slide is mounted for reciprocation toward and from the work support radially of the axis of the work support, a pair of rotatable pattern-forming rolls adapted to be rotated by engagement with a rotating workpiece, a pair of arms pivotally mounted directly on said slide for pivotal movement toward and from each other about spaced parallel axes that are disposed at right angles to the plane of reciprocation of said slide, one of said rolls being mounted on each arm for rotation about an axis parallel to the pivotal axis of its arm, actuating means for moving said slide on its support toward the workpiece and for moving said work holders toward one another, said actuating means including lost-motion means connecting said actuating means both to said slide and to said arms, and means for stopping movement of said slide toward said work support when the rolls straddle the workpiece with their axes approximately in a common plane with the axis of the vwork support, said lost-motion means being operative upon stoppage/of said last-named movement and upon continued operation of said actuating means to swing said arms toward one another to engage said rolls with the workpiece at opposite sides thereof with the axes of the rolls and workpiece lying in said common plane so that said rolls will roll a pattern on the workpiece as the rolls are rotated by their engagement with the workpiece.

2. An attachment for an automatic screw machine for rolling a pattern on a rotating workpiece, which screw machine has a rotary work support for the workpiece that is rotatably driven during operation of the machine, said attachment comprising a rectilinearly-movable slide, a support on which said slide is mounted for reciprocation toward and from the workpiece radially of the axis of the workpiece, a pair of rotatable pattern-forming rolls adapted to be rotated upon engagemnet with a rotating workpiece, a pair of arms pivotally mounted intermediate their ends on said slide for pivotal movement toward and from each other about spaced, parallel axes that are disposed at right angles to the plane of reciprocation of said slide, one of said rolls being mounted on each arm adjacent one end of the arm for rotation about an axis parallel to the pivotal axis of its arm, movable actuating means, means connecting said actuating means to said slide to move said slide toward the workpiece upon movement of said actuating means in one direction, means for stopping the last-named movement when said rolls straddle the workpiece with their axes approximately in a common plane with the axis of the workpiece, and means connecting said arms with said actuating means for swinging said arms toward one another, while said arms straddle the workpiece, upon continued movement of said actuating means in said one direction of its movement to engage said rolls with the workpiece at opposite sides thereof with the axes of the rolls and workpiece lying in said common plane, the last-named means comprising a pair of links, one of which is pivotally connected at one end to each arm at the end of the arm remote from the end adjacent which its roll -is mounted, and a member pivotally connected adjacent one end to both said links and pivotally connected adjacent its opposite end to said actuating means.

3. An attachment for an automatic screw machine for rolling a pattern on a rotating workpiece, which screw machine has a rotary work support for the workpiece that is rotatably driven during operation of the machine, said attachment comprising a support, a slide reciprocable rectilinearly on said support toward and from the workpiece radially of the axis of the workpiece, an actuating member movable in opposite directions, lost-motion connecting means connecting said actuating member to said slide to reciprocate said slide and comprising a yoke, a rod threaded into said slide at one end and passing through an opening in said yoke, a stop adjustably mounted on said rod adjacent the free end of said rod, a sleeve coaxial with the rod and slidable thereon, and a spring surrounding the rod and interposed between said sleeve and said slide, a pair of arms oscillatably mounted on said slide intermediate their ends for pivotal movement about spaced parallel axes that are disposed at right angles to the plane of reciprocation of said slide, a pattern-forming roll rotatably mounted on each arm adjacent one end of the arm and adapted to be rotated by engagement with a rotating workpiece, a link pivotally connected to each arm adjacent the opposite end of the arm, a member pivotally connected adjacent one end to the two links, means pivotally connecting said member at its opposite end to said yoke, and means for stopping the movement of said slide toward the workpiece when said rolls straddle the workpiece with their axes approximately in a common plane with the axis ofthe workpiece, said actuating member being operative to continue movement of said yoke to cause said links to swing said arms toward one another to engage said rolls with the workpiece at 'opposite sides thereof with the axes of the rolls and workpiece lying in said common plane so that the rolls will roll a pattern on the workpiece as the rolls are rotated by their engagement with lthe workpiece.

4. An attachment for an automatic screw machine for rolling a pattern on a rotating workpiece, which screw machine has a rotary work support for the workpiece that is rotatably driven during operation of the machine, said attachment comprising a rectilinearly-reciprocable slide, a support on which said slide is mounted for reciprocation toward and from the work support radially of the axis of the work support, a pair of roll holders mounted on said slide in spaced alignment for movement toward and away from one another transversely of the direction of movement of said slide, a pattern-forming roll rotatably mounted on each holder, said rolls being adapted to be rotated by engagement with the workpiece and having their rotary axes parallel but disposed at right angles to the plane of movement of said slide, said holders normally holding said rolls spaced apart a distance greater than the diameter of the workpiece whereby said rolls are` held out of workpiece-engaging position, actuating means for moving said slide and for moving said work holders toward one another, said actuating means including lostmotion means connecting said actuating means both to said slide and to said holders, and means for stopping movement of said slide Itoward said work support when said rolls straddle said work support with their axes approximately in a common plane with the axis of said work support, said lost-motion means being operative upon said stoppage of said slide and upon continued operation of said actuating means to move said holders toward one another to engage said rolls with the workpiece at opposite sides of the workpiece with the axes of the rolls and workpiece lying in said common plane, so that the rolls will roll a pattern on the workpiece as the rolls are rotated by their engagement with the workpiece.

References Cited n the tile of this patent UNITED STATES PATENTS 560,930 Rau May 26, 1896 1,145,661 Bailey July 6, 1915 1,721,729 Davenport July 23, 1929 2,001,586 Rupple May 14, 1935 2,051,159 Witte Aug. 18, 1936 2,272,592 Wilcox et al Feb. 10, 1942 2,525,805 Kirkpatrick Oct. 17, 1950 2,701,484 Bedker Feb. 8, 1955 2,748,633 Bedker June 5, 1956 2,771,799 Batchelder Nov. 27, 1956 2,790,325 Bedker Apr. 30, 1957 

